Serving as the designated hitter Sunday, Davis lasted three at-bats.
"He had to come out," A's manager Bob Melvin said. "I knew when he was taking BP in the cage, he felt it a little bit, still felt like he could play. After a couple at-bats, he just said it wasn't getting any better, it was getting a little bit worse, so we got him out of there.
"When you're dealing with some issues, you got to make the decision of whether you're going to help the team or not, and after the third at-bat, he decided, 'I'm not helping anybody right now.'"
Davis is hopeful Monday's off-day will allow him enough rest to return to the lineup Tuesday.
"It's going to be a fun series as long as we win, first and foremost," he said.
Jane Lee has covered the A's for MLB.com since 2010. This story was not subject to the approval of Major League Baseball or its clubs.